Commit | Line | Data |
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1bac305b AC |
1 | /* GDB-specific functions for operating on agent expressions. |
2 | ||
3 | Copyright 1998, 1999, 2000, 2001, 2003 Free Software Foundation, | |
4 | Inc. | |
c906108c | 5 | |
c5aa993b | 6 | This file is part of GDB. |
c906108c | 7 | |
c5aa993b JM |
8 | This program is free software; you can redistribute it and/or modify |
9 | it under the terms of the GNU General Public License as published by | |
10 | the Free Software Foundation; either version 2 of the License, or | |
11 | (at your option) any later version. | |
c906108c | 12 | |
c5aa993b JM |
13 | This program is distributed in the hope that it will be useful, |
14 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | GNU General Public License for more details. | |
c906108c | 17 | |
c5aa993b JM |
18 | You should have received a copy of the GNU General Public License |
19 | along with this program; if not, write to the Free Software | |
20 | Foundation, Inc., 59 Temple Place - Suite 330, | |
21 | Boston, MA 02111-1307, USA. */ | |
c906108c | 22 | |
c906108c SS |
23 | #include "defs.h" |
24 | #include "symtab.h" | |
25 | #include "symfile.h" | |
26 | #include "gdbtypes.h" | |
27 | #include "value.h" | |
28 | #include "expression.h" | |
29 | #include "command.h" | |
30 | #include "gdbcmd.h" | |
31 | #include "frame.h" | |
32 | #include "target.h" | |
33 | #include "ax.h" | |
34 | #include "ax-gdb.h" | |
309367d4 | 35 | #include "gdb_string.h" |
fe898f56 | 36 | #include "block.h" |
c906108c | 37 | |
6426a772 JM |
38 | /* To make sense of this file, you should read doc/agentexpr.texi. |
39 | Then look at the types and enums in ax-gdb.h. For the code itself, | |
40 | look at gen_expr, towards the bottom; that's the main function that | |
41 | looks at the GDB expressions and calls everything else to generate | |
42 | code. | |
c906108c SS |
43 | |
44 | I'm beginning to wonder whether it wouldn't be nicer to internally | |
45 | generate trees, with types, and then spit out the bytecode in | |
46 | linear form afterwards; we could generate fewer `swap', `ext', and | |
47 | `zero_ext' bytecodes that way; it would make good constant folding | |
48 | easier, too. But at the moment, I think we should be willing to | |
49 | pay for the simplicity of this code with less-than-optimal bytecode | |
50 | strings. | |
51 | ||
c5aa993b JM |
52 | Remember, "GBD" stands for "Great Britain, Dammit!" So be careful. */ |
53 | \f | |
c906108c SS |
54 | |
55 | ||
c906108c SS |
56 | /* Prototypes for local functions. */ |
57 | ||
58 | /* There's a standard order to the arguments of these functions: | |
59 | union exp_element ** --- pointer into expression | |
60 | struct agent_expr * --- agent expression buffer to generate code into | |
61 | struct axs_value * --- describes value left on top of stack */ | |
c5aa993b | 62 | |
a14ed312 KB |
63 | static struct value *const_var_ref (struct symbol *var); |
64 | static struct value *const_expr (union exp_element **pc); | |
65 | static struct value *maybe_const_expr (union exp_element **pc); | |
66 | ||
67 | static void gen_traced_pop (struct agent_expr *, struct axs_value *); | |
68 | ||
69 | static void gen_sign_extend (struct agent_expr *, struct type *); | |
70 | static void gen_extend (struct agent_expr *, struct type *); | |
71 | static void gen_fetch (struct agent_expr *, struct type *); | |
72 | static void gen_left_shift (struct agent_expr *, int); | |
73 | ||
74 | ||
75 | static void gen_frame_args_address (struct agent_expr *); | |
76 | static void gen_frame_locals_address (struct agent_expr *); | |
77 | static void gen_offset (struct agent_expr *ax, int offset); | |
78 | static void gen_sym_offset (struct agent_expr *, struct symbol *); | |
79 | static void gen_var_ref (struct agent_expr *ax, | |
80 | struct axs_value *value, struct symbol *var); | |
81 | ||
82 | ||
83 | static void gen_int_literal (struct agent_expr *ax, | |
84 | struct axs_value *value, | |
85 | LONGEST k, struct type *type); | |
86 | ||
87 | ||
88 | static void require_rvalue (struct agent_expr *ax, struct axs_value *value); | |
89 | static void gen_usual_unary (struct agent_expr *ax, struct axs_value *value); | |
90 | static int type_wider_than (struct type *type1, struct type *type2); | |
91 | static struct type *max_type (struct type *type1, struct type *type2); | |
92 | static void gen_conversion (struct agent_expr *ax, | |
93 | struct type *from, struct type *to); | |
94 | static int is_nontrivial_conversion (struct type *from, struct type *to); | |
95 | static void gen_usual_arithmetic (struct agent_expr *ax, | |
96 | struct axs_value *value1, | |
97 | struct axs_value *value2); | |
98 | static void gen_integral_promotions (struct agent_expr *ax, | |
99 | struct axs_value *value); | |
100 | static void gen_cast (struct agent_expr *ax, | |
101 | struct axs_value *value, struct type *type); | |
102 | static void gen_scale (struct agent_expr *ax, | |
103 | enum agent_op op, struct type *type); | |
104 | static void gen_add (struct agent_expr *ax, | |
105 | struct axs_value *value, | |
106 | struct axs_value *value1, | |
107 | struct axs_value *value2, char *name); | |
108 | static void gen_sub (struct agent_expr *ax, | |
109 | struct axs_value *value, | |
110 | struct axs_value *value1, struct axs_value *value2); | |
111 | static void gen_binop (struct agent_expr *ax, | |
112 | struct axs_value *value, | |
113 | struct axs_value *value1, | |
114 | struct axs_value *value2, | |
115 | enum agent_op op, | |
116 | enum agent_op op_unsigned, int may_carry, char *name); | |
117 | static void gen_logical_not (struct agent_expr *ax, struct axs_value *value); | |
118 | static void gen_complement (struct agent_expr *ax, struct axs_value *value); | |
119 | static void gen_deref (struct agent_expr *, struct axs_value *); | |
120 | static void gen_address_of (struct agent_expr *, struct axs_value *); | |
121 | static int find_field (struct type *type, char *name); | |
122 | static void gen_bitfield_ref (struct agent_expr *ax, | |
123 | struct axs_value *value, | |
124 | struct type *type, int start, int end); | |
125 | static void gen_struct_ref (struct agent_expr *ax, | |
126 | struct axs_value *value, | |
127 | char *field, | |
128 | char *operator_name, char *operand_name); | |
129 | static void gen_repeat (union exp_element **pc, | |
130 | struct agent_expr *ax, struct axs_value *value); | |
131 | static void gen_sizeof (union exp_element **pc, | |
132 | struct agent_expr *ax, struct axs_value *value); | |
133 | static void gen_expr (union exp_element **pc, | |
134 | struct agent_expr *ax, struct axs_value *value); | |
c5aa993b | 135 | |
d9fcf2fb | 136 | static void print_axs_value (struct ui_file *f, struct axs_value * value); |
a14ed312 | 137 | static void agent_command (char *exp, int from_tty); |
c906108c | 138 | \f |
c5aa993b | 139 | |
c906108c SS |
140 | /* Detecting constant expressions. */ |
141 | ||
142 | /* If the variable reference at *PC is a constant, return its value. | |
143 | Otherwise, return zero. | |
144 | ||
145 | Hey, Wally! How can a variable reference be a constant? | |
146 | ||
147 | Well, Beav, this function really handles the OP_VAR_VALUE operator, | |
148 | not specifically variable references. GDB uses OP_VAR_VALUE to | |
149 | refer to any kind of symbolic reference: function names, enum | |
150 | elements, and goto labels are all handled through the OP_VAR_VALUE | |
151 | operator, even though they're constants. It makes sense given the | |
152 | situation. | |
153 | ||
154 | Gee, Wally, don'cha wonder sometimes if data representations that | |
155 | subvert commonly accepted definitions of terms in favor of heavily | |
156 | context-specific interpretations are really just a tool of the | |
157 | programming hegemony to preserve their power and exclude the | |
158 | proletariat? */ | |
159 | ||
160 | static struct value * | |
fba45db2 | 161 | const_var_ref (struct symbol *var) |
c906108c SS |
162 | { |
163 | struct type *type = SYMBOL_TYPE (var); | |
164 | ||
165 | switch (SYMBOL_CLASS (var)) | |
166 | { | |
167 | case LOC_CONST: | |
168 | return value_from_longest (type, (LONGEST) SYMBOL_VALUE (var)); | |
169 | ||
170 | case LOC_LABEL: | |
4478b372 | 171 | return value_from_pointer (type, (CORE_ADDR) SYMBOL_VALUE_ADDRESS (var)); |
c906108c SS |
172 | |
173 | default: | |
174 | return 0; | |
175 | } | |
176 | } | |
177 | ||
178 | ||
179 | /* If the expression starting at *PC has a constant value, return it. | |
180 | Otherwise, return zero. If we return a value, then *PC will be | |
181 | advanced to the end of it. If we return zero, *PC could be | |
182 | anywhere. */ | |
183 | static struct value * | |
fba45db2 | 184 | const_expr (union exp_element **pc) |
c906108c SS |
185 | { |
186 | enum exp_opcode op = (*pc)->opcode; | |
187 | struct value *v1; | |
188 | ||
189 | switch (op) | |
190 | { | |
191 | case OP_LONG: | |
192 | { | |
193 | struct type *type = (*pc)[1].type; | |
194 | LONGEST k = (*pc)[2].longconst; | |
195 | (*pc) += 4; | |
196 | return value_from_longest (type, k); | |
197 | } | |
198 | ||
199 | case OP_VAR_VALUE: | |
200 | { | |
201 | struct value *v = const_var_ref ((*pc)[2].symbol); | |
202 | (*pc) += 4; | |
203 | return v; | |
204 | } | |
205 | ||
c5aa993b | 206 | /* We could add more operators in here. */ |
c906108c SS |
207 | |
208 | case UNOP_NEG: | |
209 | (*pc)++; | |
210 | v1 = const_expr (pc); | |
211 | if (v1) | |
212 | return value_neg (v1); | |
213 | else | |
214 | return 0; | |
215 | ||
216 | default: | |
217 | return 0; | |
218 | } | |
219 | } | |
220 | ||
221 | ||
222 | /* Like const_expr, but guarantee also that *PC is undisturbed if the | |
223 | expression is not constant. */ | |
224 | static struct value * | |
fba45db2 | 225 | maybe_const_expr (union exp_element **pc) |
c906108c SS |
226 | { |
227 | union exp_element *tentative_pc = *pc; | |
228 | struct value *v = const_expr (&tentative_pc); | |
229 | ||
230 | /* If we got a value, then update the real PC. */ | |
231 | if (v) | |
232 | *pc = tentative_pc; | |
c5aa993b | 233 | |
c906108c SS |
234 | return v; |
235 | } | |
c906108c | 236 | \f |
c5aa993b | 237 | |
c906108c SS |
238 | /* Generating bytecode from GDB expressions: general assumptions */ |
239 | ||
240 | /* Here are a few general assumptions made throughout the code; if you | |
241 | want to make a change that contradicts one of these, then you'd | |
242 | better scan things pretty thoroughly. | |
243 | ||
244 | - We assume that all values occupy one stack element. For example, | |
c5aa993b JM |
245 | sometimes we'll swap to get at the left argument to a binary |
246 | operator. If we decide that void values should occupy no stack | |
247 | elements, or that synthetic arrays (whose size is determined at | |
248 | run time, created by the `@' operator) should occupy two stack | |
249 | elements (address and length), then this will cause trouble. | |
c906108c SS |
250 | |
251 | - We assume the stack elements are infinitely wide, and that we | |
c5aa993b JM |
252 | don't have to worry what happens if the user requests an |
253 | operation that is wider than the actual interpreter's stack. | |
254 | That is, it's up to the interpreter to handle directly all the | |
255 | integer widths the user has access to. (Woe betide the language | |
256 | with bignums!) | |
c906108c SS |
257 | |
258 | - We don't support side effects. Thus, we don't have to worry about | |
c5aa993b | 259 | GCC's generalized lvalues, function calls, etc. |
c906108c SS |
260 | |
261 | - We don't support floating point. Many places where we switch on | |
c5aa993b JM |
262 | some type don't bother to include cases for floating point; there |
263 | may be even more subtle ways this assumption exists. For | |
264 | example, the arguments to % must be integers. | |
c906108c SS |
265 | |
266 | - We assume all subexpressions have a static, unchanging type. If | |
c5aa993b JM |
267 | we tried to support convenience variables, this would be a |
268 | problem. | |
c906108c SS |
269 | |
270 | - All values on the stack should always be fully zero- or | |
c5aa993b JM |
271 | sign-extended. |
272 | ||
273 | (I wasn't sure whether to choose this or its opposite --- that | |
274 | only addresses are assumed extended --- but it turns out that | |
275 | neither convention completely eliminates spurious extend | |
276 | operations (if everything is always extended, then you have to | |
277 | extend after add, because it could overflow; if nothing is | |
278 | extended, then you end up producing extends whenever you change | |
279 | sizes), and this is simpler.) */ | |
c906108c | 280 | \f |
c5aa993b | 281 | |
c906108c SS |
282 | /* Generating bytecode from GDB expressions: the `trace' kludge */ |
283 | ||
284 | /* The compiler in this file is a general-purpose mechanism for | |
285 | translating GDB expressions into bytecode. One ought to be able to | |
286 | find a million and one uses for it. | |
287 | ||
288 | However, at the moment it is HOPELESSLY BRAIN-DAMAGED for the sake | |
289 | of expediency. Let he who is without sin cast the first stone. | |
290 | ||
291 | For the data tracing facility, we need to insert `trace' bytecodes | |
292 | before each data fetch; this records all the memory that the | |
293 | expression touches in the course of evaluation, so that memory will | |
294 | be available when the user later tries to evaluate the expression | |
295 | in GDB. | |
296 | ||
297 | This should be done (I think) in a post-processing pass, that walks | |
298 | an arbitrary agent expression and inserts `trace' operations at the | |
299 | appropriate points. But it's much faster to just hack them | |
300 | directly into the code. And since we're in a crunch, that's what | |
301 | I've done. | |
302 | ||
303 | Setting the flag trace_kludge to non-zero enables the code that | |
304 | emits the trace bytecodes at the appropriate points. */ | |
305 | static int trace_kludge; | |
306 | ||
307 | /* Trace the lvalue on the stack, if it needs it. In either case, pop | |
308 | the value. Useful on the left side of a comma, and at the end of | |
309 | an expression being used for tracing. */ | |
310 | static void | |
fba45db2 | 311 | gen_traced_pop (struct agent_expr *ax, struct axs_value *value) |
c906108c SS |
312 | { |
313 | if (trace_kludge) | |
314 | switch (value->kind) | |
315 | { | |
316 | case axs_rvalue: | |
317 | /* We don't trace rvalues, just the lvalues necessary to | |
c5aa993b | 318 | produce them. So just dispose of this value. */ |
c906108c SS |
319 | ax_simple (ax, aop_pop); |
320 | break; | |
321 | ||
322 | case axs_lvalue_memory: | |
323 | { | |
324 | int length = TYPE_LENGTH (value->type); | |
325 | ||
326 | /* There's no point in trying to use a trace_quick bytecode | |
327 | here, since "trace_quick SIZE pop" is three bytes, whereas | |
328 | "const8 SIZE trace" is also three bytes, does the same | |
329 | thing, and the simplest code which generates that will also | |
330 | work correctly for objects with large sizes. */ | |
331 | ax_const_l (ax, length); | |
332 | ax_simple (ax, aop_trace); | |
333 | } | |
c5aa993b | 334 | break; |
c906108c SS |
335 | |
336 | case axs_lvalue_register: | |
337 | /* We need to mention the register somewhere in the bytecode, | |
338 | so ax_reqs will pick it up and add it to the mask of | |
339 | registers used. */ | |
340 | ax_reg (ax, value->u.reg); | |
341 | ax_simple (ax, aop_pop); | |
342 | break; | |
343 | } | |
344 | else | |
345 | /* If we're not tracing, just pop the value. */ | |
346 | ax_simple (ax, aop_pop); | |
347 | } | |
c5aa993b | 348 | \f |
c906108c SS |
349 | |
350 | ||
c906108c SS |
351 | /* Generating bytecode from GDB expressions: helper functions */ |
352 | ||
353 | /* Assume that the lower bits of the top of the stack is a value of | |
354 | type TYPE, and the upper bits are zero. Sign-extend if necessary. */ | |
355 | static void | |
fba45db2 | 356 | gen_sign_extend (struct agent_expr *ax, struct type *type) |
c906108c SS |
357 | { |
358 | /* Do we need to sign-extend this? */ | |
c5aa993b | 359 | if (!TYPE_UNSIGNED (type)) |
0004e5a2 | 360 | ax_ext (ax, TYPE_LENGTH (type) * TARGET_CHAR_BIT); |
c906108c SS |
361 | } |
362 | ||
363 | ||
364 | /* Assume the lower bits of the top of the stack hold a value of type | |
365 | TYPE, and the upper bits are garbage. Sign-extend or truncate as | |
366 | needed. */ | |
367 | static void | |
fba45db2 | 368 | gen_extend (struct agent_expr *ax, struct type *type) |
c906108c | 369 | { |
0004e5a2 | 370 | int bits = TYPE_LENGTH (type) * TARGET_CHAR_BIT; |
c906108c SS |
371 | /* I just had to. */ |
372 | ((TYPE_UNSIGNED (type) ? ax_zero_ext : ax_ext) (ax, bits)); | |
373 | } | |
374 | ||
375 | ||
376 | /* Assume that the top of the stack contains a value of type "pointer | |
377 | to TYPE"; generate code to fetch its value. Note that TYPE is the | |
378 | target type, not the pointer type. */ | |
379 | static void | |
fba45db2 | 380 | gen_fetch (struct agent_expr *ax, struct type *type) |
c906108c SS |
381 | { |
382 | if (trace_kludge) | |
383 | { | |
384 | /* Record the area of memory we're about to fetch. */ | |
385 | ax_trace_quick (ax, TYPE_LENGTH (type)); | |
386 | } | |
387 | ||
0004e5a2 | 388 | switch (TYPE_CODE (type)) |
c906108c SS |
389 | { |
390 | case TYPE_CODE_PTR: | |
391 | case TYPE_CODE_ENUM: | |
392 | case TYPE_CODE_INT: | |
393 | case TYPE_CODE_CHAR: | |
394 | /* It's a scalar value, so we know how to dereference it. How | |
395 | many bytes long is it? */ | |
0004e5a2 | 396 | switch (TYPE_LENGTH (type)) |
c906108c | 397 | { |
c5aa993b JM |
398 | case 8 / TARGET_CHAR_BIT: |
399 | ax_simple (ax, aop_ref8); | |
400 | break; | |
401 | case 16 / TARGET_CHAR_BIT: | |
402 | ax_simple (ax, aop_ref16); | |
403 | break; | |
404 | case 32 / TARGET_CHAR_BIT: | |
405 | ax_simple (ax, aop_ref32); | |
406 | break; | |
407 | case 64 / TARGET_CHAR_BIT: | |
408 | ax_simple (ax, aop_ref64); | |
409 | break; | |
c906108c SS |
410 | |
411 | /* Either our caller shouldn't have asked us to dereference | |
412 | that pointer (other code's fault), or we're not | |
413 | implementing something we should be (this code's fault). | |
414 | In any case, it's a bug the user shouldn't see. */ | |
415 | default: | |
8e65ff28 AC |
416 | internal_error (__FILE__, __LINE__, |
417 | "gen_fetch: strange size"); | |
c906108c SS |
418 | } |
419 | ||
420 | gen_sign_extend (ax, type); | |
421 | break; | |
422 | ||
423 | default: | |
424 | /* Either our caller shouldn't have asked us to dereference that | |
c5aa993b JM |
425 | pointer (other code's fault), or we're not implementing |
426 | something we should be (this code's fault). In any case, | |
427 | it's a bug the user shouldn't see. */ | |
8e65ff28 AC |
428 | internal_error (__FILE__, __LINE__, |
429 | "gen_fetch: bad type code"); | |
c906108c SS |
430 | } |
431 | } | |
432 | ||
433 | ||
434 | /* Generate code to left shift the top of the stack by DISTANCE bits, or | |
435 | right shift it by -DISTANCE bits if DISTANCE < 0. This generates | |
436 | unsigned (logical) right shifts. */ | |
437 | static void | |
fba45db2 | 438 | gen_left_shift (struct agent_expr *ax, int distance) |
c906108c SS |
439 | { |
440 | if (distance > 0) | |
441 | { | |
442 | ax_const_l (ax, distance); | |
443 | ax_simple (ax, aop_lsh); | |
444 | } | |
445 | else if (distance < 0) | |
446 | { | |
447 | ax_const_l (ax, -distance); | |
448 | ax_simple (ax, aop_rsh_unsigned); | |
449 | } | |
450 | } | |
c5aa993b | 451 | \f |
c906108c SS |
452 | |
453 | ||
c906108c SS |
454 | /* Generating bytecode from GDB expressions: symbol references */ |
455 | ||
456 | /* Generate code to push the base address of the argument portion of | |
457 | the top stack frame. */ | |
458 | static void | |
fba45db2 | 459 | gen_frame_args_address (struct agent_expr *ax) |
c906108c | 460 | { |
39d4ef09 AC |
461 | int frame_reg; |
462 | LONGEST frame_offset; | |
c906108c SS |
463 | |
464 | TARGET_VIRTUAL_FRAME_POINTER (ax->scope, &frame_reg, &frame_offset); | |
c5aa993b | 465 | ax_reg (ax, frame_reg); |
c906108c SS |
466 | gen_offset (ax, frame_offset); |
467 | } | |
468 | ||
469 | ||
470 | /* Generate code to push the base address of the locals portion of the | |
471 | top stack frame. */ | |
472 | static void | |
fba45db2 | 473 | gen_frame_locals_address (struct agent_expr *ax) |
c906108c | 474 | { |
39d4ef09 AC |
475 | int frame_reg; |
476 | LONGEST frame_offset; | |
c906108c SS |
477 | |
478 | TARGET_VIRTUAL_FRAME_POINTER (ax->scope, &frame_reg, &frame_offset); | |
c5aa993b | 479 | ax_reg (ax, frame_reg); |
c906108c SS |
480 | gen_offset (ax, frame_offset); |
481 | } | |
482 | ||
483 | ||
484 | /* Generate code to add OFFSET to the top of the stack. Try to | |
485 | generate short and readable code. We use this for getting to | |
486 | variables on the stack, and structure members. If we were | |
487 | programming in ML, it would be clearer why these are the same | |
488 | thing. */ | |
489 | static void | |
fba45db2 | 490 | gen_offset (struct agent_expr *ax, int offset) |
c906108c SS |
491 | { |
492 | /* It would suffice to simply push the offset and add it, but this | |
493 | makes it easier to read positive and negative offsets in the | |
494 | bytecode. */ | |
495 | if (offset > 0) | |
496 | { | |
497 | ax_const_l (ax, offset); | |
498 | ax_simple (ax, aop_add); | |
499 | } | |
500 | else if (offset < 0) | |
501 | { | |
502 | ax_const_l (ax, -offset); | |
503 | ax_simple (ax, aop_sub); | |
504 | } | |
505 | } | |
506 | ||
507 | ||
508 | /* In many cases, a symbol's value is the offset from some other | |
509 | address (stack frame, base register, etc.) Generate code to add | |
510 | VAR's value to the top of the stack. */ | |
511 | static void | |
fba45db2 | 512 | gen_sym_offset (struct agent_expr *ax, struct symbol *var) |
c906108c SS |
513 | { |
514 | gen_offset (ax, SYMBOL_VALUE (var)); | |
515 | } | |
516 | ||
517 | ||
518 | /* Generate code for a variable reference to AX. The variable is the | |
519 | symbol VAR. Set VALUE to describe the result. */ | |
520 | ||
521 | static void | |
fba45db2 | 522 | gen_var_ref (struct agent_expr *ax, struct axs_value *value, struct symbol *var) |
c906108c SS |
523 | { |
524 | /* Dereference any typedefs. */ | |
525 | value->type = check_typedef (SYMBOL_TYPE (var)); | |
526 | ||
527 | /* I'm imitating the code in read_var_value. */ | |
528 | switch (SYMBOL_CLASS (var)) | |
529 | { | |
530 | case LOC_CONST: /* A constant, like an enum value. */ | |
531 | ax_const_l (ax, (LONGEST) SYMBOL_VALUE (var)); | |
532 | value->kind = axs_rvalue; | |
533 | break; | |
534 | ||
535 | case LOC_LABEL: /* A goto label, being used as a value. */ | |
536 | ax_const_l (ax, (LONGEST) SYMBOL_VALUE_ADDRESS (var)); | |
537 | value->kind = axs_rvalue; | |
538 | break; | |
539 | ||
540 | case LOC_CONST_BYTES: | |
8e65ff28 AC |
541 | internal_error (__FILE__, __LINE__, |
542 | "gen_var_ref: LOC_CONST_BYTES symbols are not supported"); | |
c906108c SS |
543 | |
544 | /* Variable at a fixed location in memory. Easy. */ | |
545 | case LOC_STATIC: | |
546 | /* Push the address of the variable. */ | |
547 | ax_const_l (ax, SYMBOL_VALUE_ADDRESS (var)); | |
548 | value->kind = axs_lvalue_memory; | |
549 | break; | |
550 | ||
551 | case LOC_ARG: /* var lives in argument area of frame */ | |
552 | gen_frame_args_address (ax); | |
553 | gen_sym_offset (ax, var); | |
554 | value->kind = axs_lvalue_memory; | |
555 | break; | |
556 | ||
557 | case LOC_REF_ARG: /* As above, but the frame slot really | |
558 | holds the address of the variable. */ | |
559 | gen_frame_args_address (ax); | |
560 | gen_sym_offset (ax, var); | |
561 | /* Don't assume any particular pointer size. */ | |
562 | gen_fetch (ax, lookup_pointer_type (builtin_type_void)); | |
563 | value->kind = axs_lvalue_memory; | |
564 | break; | |
565 | ||
566 | case LOC_LOCAL: /* var lives in locals area of frame */ | |
567 | case LOC_LOCAL_ARG: | |
568 | gen_frame_locals_address (ax); | |
569 | gen_sym_offset (ax, var); | |
570 | value->kind = axs_lvalue_memory; | |
571 | break; | |
572 | ||
573 | case LOC_BASEREG: /* relative to some base register */ | |
574 | case LOC_BASEREG_ARG: | |
575 | ax_reg (ax, SYMBOL_BASEREG (var)); | |
576 | gen_sym_offset (ax, var); | |
577 | value->kind = axs_lvalue_memory; | |
578 | break; | |
579 | ||
580 | case LOC_TYPEDEF: | |
581 | error ("Cannot compute value of typedef `%s'.", | |
de5ad195 | 582 | SYMBOL_PRINT_NAME (var)); |
c906108c SS |
583 | break; |
584 | ||
585 | case LOC_BLOCK: | |
586 | ax_const_l (ax, BLOCK_START (SYMBOL_BLOCK_VALUE (var))); | |
587 | value->kind = axs_rvalue; | |
588 | break; | |
589 | ||
590 | case LOC_REGISTER: | |
591 | case LOC_REGPARM: | |
592 | /* Don't generate any code at all; in the process of treating | |
593 | this as an lvalue or rvalue, the caller will generate the | |
594 | right code. */ | |
595 | value->kind = axs_lvalue_register; | |
596 | value->u.reg = SYMBOL_VALUE (var); | |
597 | break; | |
598 | ||
599 | /* A lot like LOC_REF_ARG, but the pointer lives directly in a | |
c5aa993b JM |
600 | register, not on the stack. Simpler than LOC_REGISTER and |
601 | LOC_REGPARM, because it's just like any other case where the | |
602 | thing has a real address. */ | |
c906108c SS |
603 | case LOC_REGPARM_ADDR: |
604 | ax_reg (ax, SYMBOL_VALUE (var)); | |
605 | value->kind = axs_lvalue_memory; | |
606 | break; | |
607 | ||
608 | case LOC_UNRESOLVED: | |
609 | { | |
c5aa993b | 610 | struct minimal_symbol *msym |
22abf04a | 611 | = lookup_minimal_symbol (DEPRECATED_SYMBOL_NAME (var), NULL, NULL); |
c5aa993b | 612 | if (!msym) |
de5ad195 | 613 | error ("Couldn't resolve symbol `%s'.", SYMBOL_PRINT_NAME (var)); |
c5aa993b | 614 | |
c906108c SS |
615 | /* Push the address of the variable. */ |
616 | ax_const_l (ax, SYMBOL_VALUE_ADDRESS (msym)); | |
617 | value->kind = axs_lvalue_memory; | |
618 | } | |
c5aa993b | 619 | break; |
c906108c | 620 | |
a55cc764 DJ |
621 | case LOC_COMPUTED: |
622 | case LOC_COMPUTED_ARG: | |
623 | (*SYMBOL_LOCATION_FUNCS (var)->tracepoint_var_ref) (var, ax, value); | |
624 | break; | |
625 | ||
c906108c SS |
626 | case LOC_OPTIMIZED_OUT: |
627 | error ("The variable `%s' has been optimized out.", | |
de5ad195 | 628 | SYMBOL_PRINT_NAME (var)); |
c906108c SS |
629 | break; |
630 | ||
631 | default: | |
632 | error ("Cannot find value of botched symbol `%s'.", | |
de5ad195 | 633 | SYMBOL_PRINT_NAME (var)); |
c906108c SS |
634 | break; |
635 | } | |
636 | } | |
c5aa993b | 637 | \f |
c906108c SS |
638 | |
639 | ||
c906108c SS |
640 | /* Generating bytecode from GDB expressions: literals */ |
641 | ||
642 | static void | |
fba45db2 KB |
643 | gen_int_literal (struct agent_expr *ax, struct axs_value *value, LONGEST k, |
644 | struct type *type) | |
c906108c SS |
645 | { |
646 | ax_const_l (ax, k); | |
647 | value->kind = axs_rvalue; | |
648 | value->type = type; | |
649 | } | |
c5aa993b | 650 | \f |
c906108c SS |
651 | |
652 | ||
c906108c SS |
653 | /* Generating bytecode from GDB expressions: unary conversions, casts */ |
654 | ||
655 | /* Take what's on the top of the stack (as described by VALUE), and | |
656 | try to make an rvalue out of it. Signal an error if we can't do | |
657 | that. */ | |
658 | static void | |
fba45db2 | 659 | require_rvalue (struct agent_expr *ax, struct axs_value *value) |
c906108c SS |
660 | { |
661 | switch (value->kind) | |
662 | { | |
663 | case axs_rvalue: | |
664 | /* It's already an rvalue. */ | |
665 | break; | |
666 | ||
667 | case axs_lvalue_memory: | |
668 | /* The top of stack is the address of the object. Dereference. */ | |
669 | gen_fetch (ax, value->type); | |
670 | break; | |
671 | ||
672 | case axs_lvalue_register: | |
673 | /* There's nothing on the stack, but value->u.reg is the | |
674 | register number containing the value. | |
675 | ||
c5aa993b JM |
676 | When we add floating-point support, this is going to have to |
677 | change. What about SPARC register pairs, for example? */ | |
c906108c SS |
678 | ax_reg (ax, value->u.reg); |
679 | gen_extend (ax, value->type); | |
680 | break; | |
681 | } | |
682 | ||
683 | value->kind = axs_rvalue; | |
684 | } | |
685 | ||
686 | ||
687 | /* Assume the top of the stack is described by VALUE, and perform the | |
688 | usual unary conversions. This is motivated by ANSI 6.2.2, but of | |
689 | course GDB expressions are not ANSI; they're the mishmash union of | |
690 | a bunch of languages. Rah. | |
691 | ||
692 | NOTE! This function promises to produce an rvalue only when the | |
693 | incoming value is of an appropriate type. In other words, the | |
694 | consumer of the value this function produces may assume the value | |
695 | is an rvalue only after checking its type. | |
696 | ||
697 | The immediate issue is that if the user tries to use a structure or | |
698 | union as an operand of, say, the `+' operator, we don't want to try | |
699 | to convert that structure to an rvalue; require_rvalue will bomb on | |
700 | structs and unions. Rather, we want to simply pass the struct | |
701 | lvalue through unchanged, and let `+' raise an error. */ | |
702 | ||
703 | static void | |
fba45db2 | 704 | gen_usual_unary (struct agent_expr *ax, struct axs_value *value) |
c906108c SS |
705 | { |
706 | /* We don't have to generate any code for the usual integral | |
707 | conversions, since values are always represented as full-width on | |
708 | the stack. Should we tweak the type? */ | |
709 | ||
710 | /* Some types require special handling. */ | |
0004e5a2 | 711 | switch (TYPE_CODE (value->type)) |
c906108c SS |
712 | { |
713 | /* Functions get converted to a pointer to the function. */ | |
714 | case TYPE_CODE_FUNC: | |
715 | value->type = lookup_pointer_type (value->type); | |
716 | value->kind = axs_rvalue; /* Should always be true, but just in case. */ | |
717 | break; | |
718 | ||
719 | /* Arrays get converted to a pointer to their first element, and | |
c5aa993b | 720 | are no longer an lvalue. */ |
c906108c SS |
721 | case TYPE_CODE_ARRAY: |
722 | { | |
723 | struct type *elements = TYPE_TARGET_TYPE (value->type); | |
724 | value->type = lookup_pointer_type (elements); | |
725 | value->kind = axs_rvalue; | |
726 | /* We don't need to generate any code; the address of the array | |
727 | is also the address of its first element. */ | |
728 | } | |
c5aa993b | 729 | break; |
c906108c | 730 | |
c5aa993b JM |
731 | /* Don't try to convert structures and unions to rvalues. Let the |
732 | consumer signal an error. */ | |
c906108c SS |
733 | case TYPE_CODE_STRUCT: |
734 | case TYPE_CODE_UNION: | |
735 | return; | |
736 | ||
737 | /* If the value is an enum, call it an integer. */ | |
738 | case TYPE_CODE_ENUM: | |
739 | value->type = builtin_type_int; | |
740 | break; | |
741 | } | |
742 | ||
743 | /* If the value is an lvalue, dereference it. */ | |
744 | require_rvalue (ax, value); | |
745 | } | |
746 | ||
747 | ||
748 | /* Return non-zero iff the type TYPE1 is considered "wider" than the | |
749 | type TYPE2, according to the rules described in gen_usual_arithmetic. */ | |
750 | static int | |
fba45db2 | 751 | type_wider_than (struct type *type1, struct type *type2) |
c906108c SS |
752 | { |
753 | return (TYPE_LENGTH (type1) > TYPE_LENGTH (type2) | |
754 | || (TYPE_LENGTH (type1) == TYPE_LENGTH (type2) | |
755 | && TYPE_UNSIGNED (type1) | |
c5aa993b | 756 | && !TYPE_UNSIGNED (type2))); |
c906108c SS |
757 | } |
758 | ||
759 | ||
760 | /* Return the "wider" of the two types TYPE1 and TYPE2. */ | |
761 | static struct type * | |
fba45db2 | 762 | max_type (struct type *type1, struct type *type2) |
c906108c SS |
763 | { |
764 | return type_wider_than (type1, type2) ? type1 : type2; | |
765 | } | |
766 | ||
767 | ||
768 | /* Generate code to convert a scalar value of type FROM to type TO. */ | |
769 | static void | |
fba45db2 | 770 | gen_conversion (struct agent_expr *ax, struct type *from, struct type *to) |
c906108c SS |
771 | { |
772 | /* Perhaps there is a more graceful way to state these rules. */ | |
773 | ||
774 | /* If we're converting to a narrower type, then we need to clear out | |
775 | the upper bits. */ | |
776 | if (TYPE_LENGTH (to) < TYPE_LENGTH (from)) | |
777 | gen_extend (ax, from); | |
778 | ||
779 | /* If the two values have equal width, but different signednesses, | |
780 | then we need to extend. */ | |
781 | else if (TYPE_LENGTH (to) == TYPE_LENGTH (from)) | |
782 | { | |
783 | if (TYPE_UNSIGNED (from) != TYPE_UNSIGNED (to)) | |
784 | gen_extend (ax, to); | |
785 | } | |
786 | ||
787 | /* If we're converting to a wider type, and becoming unsigned, then | |
788 | we need to zero out any possible sign bits. */ | |
789 | else if (TYPE_LENGTH (to) > TYPE_LENGTH (from)) | |
790 | { | |
791 | if (TYPE_UNSIGNED (to)) | |
792 | gen_extend (ax, to); | |
793 | } | |
794 | } | |
795 | ||
796 | ||
797 | /* Return non-zero iff the type FROM will require any bytecodes to be | |
798 | emitted to be converted to the type TO. */ | |
799 | static int | |
fba45db2 | 800 | is_nontrivial_conversion (struct type *from, struct type *to) |
c906108c SS |
801 | { |
802 | struct agent_expr *ax = new_agent_expr (0); | |
803 | int nontrivial; | |
804 | ||
805 | /* Actually generate the code, and see if anything came out. At the | |
806 | moment, it would be trivial to replicate the code in | |
807 | gen_conversion here, but in the future, when we're supporting | |
808 | floating point and the like, it may not be. Doing things this | |
809 | way allows this function to be independent of the logic in | |
810 | gen_conversion. */ | |
811 | gen_conversion (ax, from, to); | |
812 | nontrivial = ax->len > 0; | |
813 | free_agent_expr (ax); | |
814 | return nontrivial; | |
815 | } | |
816 | ||
817 | ||
818 | /* Generate code to perform the "usual arithmetic conversions" (ANSI C | |
819 | 6.2.1.5) for the two operands of an arithmetic operator. This | |
820 | effectively finds a "least upper bound" type for the two arguments, | |
821 | and promotes each argument to that type. *VALUE1 and *VALUE2 | |
822 | describe the values as they are passed in, and as they are left. */ | |
823 | static void | |
fba45db2 KB |
824 | gen_usual_arithmetic (struct agent_expr *ax, struct axs_value *value1, |
825 | struct axs_value *value2) | |
c906108c SS |
826 | { |
827 | /* Do the usual binary conversions. */ | |
828 | if (TYPE_CODE (value1->type) == TYPE_CODE_INT | |
829 | && TYPE_CODE (value2->type) == TYPE_CODE_INT) | |
830 | { | |
831 | /* The ANSI integral promotions seem to work this way: Order the | |
c5aa993b JM |
832 | integer types by size, and then by signedness: an n-bit |
833 | unsigned type is considered "wider" than an n-bit signed | |
834 | type. Promote to the "wider" of the two types, and always | |
835 | promote at least to int. */ | |
c906108c SS |
836 | struct type *target = max_type (builtin_type_int, |
837 | max_type (value1->type, value2->type)); | |
838 | ||
839 | /* Deal with value2, on the top of the stack. */ | |
840 | gen_conversion (ax, value2->type, target); | |
841 | ||
842 | /* Deal with value1, not on the top of the stack. Don't | |
843 | generate the `swap' instructions if we're not actually going | |
844 | to do anything. */ | |
845 | if (is_nontrivial_conversion (value1->type, target)) | |
846 | { | |
847 | ax_simple (ax, aop_swap); | |
848 | gen_conversion (ax, value1->type, target); | |
849 | ax_simple (ax, aop_swap); | |
850 | } | |
851 | ||
852 | value1->type = value2->type = target; | |
853 | } | |
854 | } | |
855 | ||
856 | ||
857 | /* Generate code to perform the integral promotions (ANSI 6.2.1.1) on | |
858 | the value on the top of the stack, as described by VALUE. Assume | |
859 | the value has integral type. */ | |
860 | static void | |
fba45db2 | 861 | gen_integral_promotions (struct agent_expr *ax, struct axs_value *value) |
c906108c | 862 | { |
c5aa993b | 863 | if (!type_wider_than (value->type, builtin_type_int)) |
c906108c SS |
864 | { |
865 | gen_conversion (ax, value->type, builtin_type_int); | |
866 | value->type = builtin_type_int; | |
867 | } | |
c5aa993b | 868 | else if (!type_wider_than (value->type, builtin_type_unsigned_int)) |
c906108c SS |
869 | { |
870 | gen_conversion (ax, value->type, builtin_type_unsigned_int); | |
871 | value->type = builtin_type_unsigned_int; | |
872 | } | |
873 | } | |
874 | ||
875 | ||
876 | /* Generate code for a cast to TYPE. */ | |
877 | static void | |
fba45db2 | 878 | gen_cast (struct agent_expr *ax, struct axs_value *value, struct type *type) |
c906108c SS |
879 | { |
880 | /* GCC does allow casts to yield lvalues, so this should be fixed | |
881 | before merging these changes into the trunk. */ | |
882 | require_rvalue (ax, value); | |
883 | /* Dereference typedefs. */ | |
884 | type = check_typedef (type); | |
885 | ||
0004e5a2 | 886 | switch (TYPE_CODE (type)) |
c906108c SS |
887 | { |
888 | case TYPE_CODE_PTR: | |
889 | /* It's implementation-defined, and I'll bet this is what GCC | |
890 | does. */ | |
891 | break; | |
892 | ||
893 | case TYPE_CODE_ARRAY: | |
894 | case TYPE_CODE_STRUCT: | |
895 | case TYPE_CODE_UNION: | |
896 | case TYPE_CODE_FUNC: | |
897 | error ("Illegal type cast: intended type must be scalar."); | |
898 | ||
899 | case TYPE_CODE_ENUM: | |
900 | /* We don't have to worry about the size of the value, because | |
901 | all our integral values are fully sign-extended, and when | |
902 | casting pointers we can do anything we like. Is there any | |
903 | way for us to actually know what GCC actually does with a | |
904 | cast like this? */ | |
905 | value->type = type; | |
906 | break; | |
c5aa993b | 907 | |
c906108c SS |
908 | case TYPE_CODE_INT: |
909 | gen_conversion (ax, value->type, type); | |
910 | break; | |
911 | ||
912 | case TYPE_CODE_VOID: | |
913 | /* We could pop the value, and rely on everyone else to check | |
c5aa993b JM |
914 | the type and notice that this value doesn't occupy a stack |
915 | slot. But for now, leave the value on the stack, and | |
916 | preserve the "value == stack element" assumption. */ | |
c906108c SS |
917 | break; |
918 | ||
919 | default: | |
920 | error ("Casts to requested type are not yet implemented."); | |
921 | } | |
922 | ||
923 | value->type = type; | |
924 | } | |
c5aa993b | 925 | \f |
c906108c SS |
926 | |
927 | ||
c906108c SS |
928 | /* Generating bytecode from GDB expressions: arithmetic */ |
929 | ||
930 | /* Scale the integer on the top of the stack by the size of the target | |
931 | of the pointer type TYPE. */ | |
932 | static void | |
fba45db2 | 933 | gen_scale (struct agent_expr *ax, enum agent_op op, struct type *type) |
c906108c SS |
934 | { |
935 | struct type *element = TYPE_TARGET_TYPE (type); | |
936 | ||
0004e5a2 | 937 | if (TYPE_LENGTH (element) != 1) |
c906108c | 938 | { |
0004e5a2 | 939 | ax_const_l (ax, TYPE_LENGTH (element)); |
c906108c SS |
940 | ax_simple (ax, op); |
941 | } | |
942 | } | |
943 | ||
944 | ||
945 | /* Generate code for an addition; non-trivial because we deal with | |
946 | pointer arithmetic. We set VALUE to describe the result value; we | |
947 | assume VALUE1 and VALUE2 describe the two operands, and that | |
948 | they've undergone the usual binary conversions. Used by both | |
949 | BINOP_ADD and BINOP_SUBSCRIPT. NAME is used in error messages. */ | |
950 | static void | |
fba45db2 KB |
951 | gen_add (struct agent_expr *ax, struct axs_value *value, |
952 | struct axs_value *value1, struct axs_value *value2, char *name) | |
c906108c SS |
953 | { |
954 | /* Is it INT+PTR? */ | |
0004e5a2 DJ |
955 | if (TYPE_CODE (value1->type) == TYPE_CODE_INT |
956 | && TYPE_CODE (value2->type) == TYPE_CODE_PTR) | |
c906108c SS |
957 | { |
958 | /* Swap the values and proceed normally. */ | |
959 | ax_simple (ax, aop_swap); | |
960 | gen_scale (ax, aop_mul, value2->type); | |
961 | ax_simple (ax, aop_add); | |
c5aa993b | 962 | gen_extend (ax, value2->type); /* Catch overflow. */ |
c906108c SS |
963 | value->type = value2->type; |
964 | } | |
965 | ||
966 | /* Is it PTR+INT? */ | |
0004e5a2 DJ |
967 | else if (TYPE_CODE (value1->type) == TYPE_CODE_PTR |
968 | && TYPE_CODE (value2->type) == TYPE_CODE_INT) | |
c906108c SS |
969 | { |
970 | gen_scale (ax, aop_mul, value1->type); | |
971 | ax_simple (ax, aop_add); | |
c5aa993b | 972 | gen_extend (ax, value1->type); /* Catch overflow. */ |
c906108c SS |
973 | value->type = value1->type; |
974 | } | |
975 | ||
976 | /* Must be number + number; the usual binary conversions will have | |
977 | brought them both to the same width. */ | |
0004e5a2 DJ |
978 | else if (TYPE_CODE (value1->type) == TYPE_CODE_INT |
979 | && TYPE_CODE (value2->type) == TYPE_CODE_INT) | |
c906108c SS |
980 | { |
981 | ax_simple (ax, aop_add); | |
c5aa993b | 982 | gen_extend (ax, value1->type); /* Catch overflow. */ |
c906108c SS |
983 | value->type = value1->type; |
984 | } | |
985 | ||
986 | else | |
987 | error ("Illegal combination of types in %s.", name); | |
988 | ||
989 | value->kind = axs_rvalue; | |
990 | } | |
991 | ||
992 | ||
993 | /* Generate code for an addition; non-trivial because we have to deal | |
994 | with pointer arithmetic. We set VALUE to describe the result | |
995 | value; we assume VALUE1 and VALUE2 describe the two operands, and | |
996 | that they've undergone the usual binary conversions. */ | |
997 | static void | |
fba45db2 KB |
998 | gen_sub (struct agent_expr *ax, struct axs_value *value, |
999 | struct axs_value *value1, struct axs_value *value2) | |
c906108c | 1000 | { |
0004e5a2 | 1001 | if (TYPE_CODE (value1->type) == TYPE_CODE_PTR) |
c906108c SS |
1002 | { |
1003 | /* Is it PTR - INT? */ | |
0004e5a2 | 1004 | if (TYPE_CODE (value2->type) == TYPE_CODE_INT) |
c906108c SS |
1005 | { |
1006 | gen_scale (ax, aop_mul, value1->type); | |
1007 | ax_simple (ax, aop_sub); | |
c5aa993b | 1008 | gen_extend (ax, value1->type); /* Catch overflow. */ |
c906108c SS |
1009 | value->type = value1->type; |
1010 | } | |
1011 | ||
1012 | /* Is it PTR - PTR? Strictly speaking, the types ought to | |
c5aa993b JM |
1013 | match, but this is what the normal GDB expression evaluator |
1014 | tests for. */ | |
0004e5a2 | 1015 | else if (TYPE_CODE (value2->type) == TYPE_CODE_PTR |
c906108c SS |
1016 | && (TYPE_LENGTH (TYPE_TARGET_TYPE (value1->type)) |
1017 | == TYPE_LENGTH (TYPE_TARGET_TYPE (value2->type)))) | |
1018 | { | |
1019 | ax_simple (ax, aop_sub); | |
1020 | gen_scale (ax, aop_div_unsigned, value1->type); | |
c5aa993b | 1021 | value->type = builtin_type_long; /* FIXME --- should be ptrdiff_t */ |
c906108c SS |
1022 | } |
1023 | else | |
1024 | error ("\ | |
1025 | First argument of `-' is a pointer, but second argument is neither\n\ | |
1026 | an integer nor a pointer of the same type."); | |
1027 | } | |
1028 | ||
1029 | /* Must be number + number. */ | |
0004e5a2 DJ |
1030 | else if (TYPE_CODE (value1->type) == TYPE_CODE_INT |
1031 | && TYPE_CODE (value2->type) == TYPE_CODE_INT) | |
c906108c SS |
1032 | { |
1033 | ax_simple (ax, aop_sub); | |
c5aa993b | 1034 | gen_extend (ax, value1->type); /* Catch overflow. */ |
c906108c SS |
1035 | value->type = value1->type; |
1036 | } | |
c5aa993b | 1037 | |
c906108c SS |
1038 | else |
1039 | error ("Illegal combination of types in subtraction."); | |
1040 | ||
1041 | value->kind = axs_rvalue; | |
1042 | } | |
1043 | ||
1044 | /* Generate code for a binary operator that doesn't do pointer magic. | |
1045 | We set VALUE to describe the result value; we assume VALUE1 and | |
1046 | VALUE2 describe the two operands, and that they've undergone the | |
1047 | usual binary conversions. MAY_CARRY should be non-zero iff the | |
1048 | result needs to be extended. NAME is the English name of the | |
1049 | operator, used in error messages */ | |
1050 | static void | |
fba45db2 KB |
1051 | gen_binop (struct agent_expr *ax, struct axs_value *value, |
1052 | struct axs_value *value1, struct axs_value *value2, enum agent_op op, | |
1053 | enum agent_op op_unsigned, int may_carry, char *name) | |
c906108c SS |
1054 | { |
1055 | /* We only handle INT op INT. */ | |
0004e5a2 DJ |
1056 | if ((TYPE_CODE (value1->type) != TYPE_CODE_INT) |
1057 | || (TYPE_CODE (value2->type) != TYPE_CODE_INT)) | |
c906108c | 1058 | error ("Illegal combination of types in %s.", name); |
c5aa993b | 1059 | |
c906108c SS |
1060 | ax_simple (ax, |
1061 | TYPE_UNSIGNED (value1->type) ? op_unsigned : op); | |
1062 | if (may_carry) | |
c5aa993b | 1063 | gen_extend (ax, value1->type); /* catch overflow */ |
c906108c SS |
1064 | value->type = value1->type; |
1065 | value->kind = axs_rvalue; | |
1066 | } | |
1067 | ||
1068 | ||
1069 | static void | |
fba45db2 | 1070 | gen_logical_not (struct agent_expr *ax, struct axs_value *value) |
c906108c SS |
1071 | { |
1072 | if (TYPE_CODE (value->type) != TYPE_CODE_INT | |
1073 | && TYPE_CODE (value->type) != TYPE_CODE_PTR) | |
1074 | error ("Illegal type of operand to `!'."); | |
1075 | ||
1076 | gen_usual_unary (ax, value); | |
1077 | ax_simple (ax, aop_log_not); | |
1078 | value->type = builtin_type_int; | |
1079 | } | |
1080 | ||
1081 | ||
1082 | static void | |
fba45db2 | 1083 | gen_complement (struct agent_expr *ax, struct axs_value *value) |
c906108c SS |
1084 | { |
1085 | if (TYPE_CODE (value->type) != TYPE_CODE_INT) | |
1086 | error ("Illegal type of operand to `~'."); | |
1087 | ||
1088 | gen_usual_unary (ax, value); | |
1089 | gen_integral_promotions (ax, value); | |
1090 | ax_simple (ax, aop_bit_not); | |
1091 | gen_extend (ax, value->type); | |
1092 | } | |
c5aa993b | 1093 | \f |
c906108c SS |
1094 | |
1095 | ||
c906108c SS |
1096 | /* Generating bytecode from GDB expressions: * & . -> @ sizeof */ |
1097 | ||
1098 | /* Dereference the value on the top of the stack. */ | |
1099 | static void | |
fba45db2 | 1100 | gen_deref (struct agent_expr *ax, struct axs_value *value) |
c906108c SS |
1101 | { |
1102 | /* The caller should check the type, because several operators use | |
1103 | this, and we don't know what error message to generate. */ | |
0004e5a2 | 1104 | if (TYPE_CODE (value->type) != TYPE_CODE_PTR) |
8e65ff28 AC |
1105 | internal_error (__FILE__, __LINE__, |
1106 | "gen_deref: expected a pointer"); | |
c906108c SS |
1107 | |
1108 | /* We've got an rvalue now, which is a pointer. We want to yield an | |
1109 | lvalue, whose address is exactly that pointer. So we don't | |
1110 | actually emit any code; we just change the type from "Pointer to | |
1111 | T" to "T", and mark the value as an lvalue in memory. Leave it | |
1112 | to the consumer to actually dereference it. */ | |
1113 | value->type = check_typedef (TYPE_TARGET_TYPE (value->type)); | |
0004e5a2 | 1114 | value->kind = ((TYPE_CODE (value->type) == TYPE_CODE_FUNC) |
c906108c SS |
1115 | ? axs_rvalue : axs_lvalue_memory); |
1116 | } | |
1117 | ||
1118 | ||
1119 | /* Produce the address of the lvalue on the top of the stack. */ | |
1120 | static void | |
fba45db2 | 1121 | gen_address_of (struct agent_expr *ax, struct axs_value *value) |
c906108c SS |
1122 | { |
1123 | /* Special case for taking the address of a function. The ANSI | |
1124 | standard describes this as a special case, too, so this | |
1125 | arrangement is not without motivation. */ | |
0004e5a2 | 1126 | if (TYPE_CODE (value->type) == TYPE_CODE_FUNC) |
c906108c SS |
1127 | /* The value's already an rvalue on the stack, so we just need to |
1128 | change the type. */ | |
1129 | value->type = lookup_pointer_type (value->type); | |
1130 | else | |
1131 | switch (value->kind) | |
1132 | { | |
1133 | case axs_rvalue: | |
1134 | error ("Operand of `&' is an rvalue, which has no address."); | |
1135 | ||
1136 | case axs_lvalue_register: | |
1137 | error ("Operand of `&' is in a register, and has no address."); | |
1138 | ||
1139 | case axs_lvalue_memory: | |
1140 | value->kind = axs_rvalue; | |
1141 | value->type = lookup_pointer_type (value->type); | |
1142 | break; | |
1143 | } | |
1144 | } | |
1145 | ||
1146 | ||
1147 | /* A lot of this stuff will have to change to support C++. But we're | |
1148 | not going to deal with that at the moment. */ | |
1149 | ||
1150 | /* Find the field in the structure type TYPE named NAME, and return | |
1151 | its index in TYPE's field array. */ | |
1152 | static int | |
fba45db2 | 1153 | find_field (struct type *type, char *name) |
c906108c SS |
1154 | { |
1155 | int i; | |
1156 | ||
1157 | CHECK_TYPEDEF (type); | |
1158 | ||
1159 | /* Make sure this isn't C++. */ | |
1160 | if (TYPE_N_BASECLASSES (type) != 0) | |
8e65ff28 AC |
1161 | internal_error (__FILE__, __LINE__, |
1162 | "find_field: derived classes supported"); | |
c906108c SS |
1163 | |
1164 | for (i = 0; i < TYPE_NFIELDS (type); i++) | |
1165 | { | |
1166 | char *this_name = TYPE_FIELD_NAME (type, i); | |
1167 | ||
bde58177 | 1168 | if (this_name && strcmp (name, this_name) == 0) |
c906108c SS |
1169 | return i; |
1170 | ||
1171 | if (this_name[0] == '\0') | |
8e65ff28 AC |
1172 | internal_error (__FILE__, __LINE__, |
1173 | "find_field: anonymous unions not supported"); | |
c906108c SS |
1174 | } |
1175 | ||
1176 | error ("Couldn't find member named `%s' in struct/union `%s'", | |
7495dfdb | 1177 | name, TYPE_TAG_NAME (type)); |
c906108c SS |
1178 | |
1179 | return 0; | |
1180 | } | |
1181 | ||
1182 | ||
1183 | /* Generate code to push the value of a bitfield of a structure whose | |
1184 | address is on the top of the stack. START and END give the | |
1185 | starting and one-past-ending *bit* numbers of the field within the | |
1186 | structure. */ | |
1187 | static void | |
fba45db2 KB |
1188 | gen_bitfield_ref (struct agent_expr *ax, struct axs_value *value, |
1189 | struct type *type, int start, int end) | |
c906108c SS |
1190 | { |
1191 | /* Note that ops[i] fetches 8 << i bits. */ | |
1192 | static enum agent_op ops[] | |
c5aa993b JM |
1193 | = |
1194 | {aop_ref8, aop_ref16, aop_ref32, aop_ref64}; | |
c906108c SS |
1195 | static int num_ops = (sizeof (ops) / sizeof (ops[0])); |
1196 | ||
1197 | /* We don't want to touch any byte that the bitfield doesn't | |
1198 | actually occupy; we shouldn't make any accesses we're not | |
1199 | explicitly permitted to. We rely here on the fact that the | |
1200 | bytecode `ref' operators work on unaligned addresses. | |
1201 | ||
1202 | It takes some fancy footwork to get the stack to work the way | |
1203 | we'd like. Say we're retrieving a bitfield that requires three | |
1204 | fetches. Initially, the stack just contains the address: | |
c5aa993b | 1205 | addr |
c906108c | 1206 | For the first fetch, we duplicate the address |
c5aa993b | 1207 | addr addr |
c906108c SS |
1208 | then add the byte offset, do the fetch, and shift and mask as |
1209 | needed, yielding a fragment of the value, properly aligned for | |
1210 | the final bitwise or: | |
c5aa993b | 1211 | addr frag1 |
c906108c | 1212 | then we swap, and repeat the process: |
c5aa993b JM |
1213 | frag1 addr --- address on top |
1214 | frag1 addr addr --- duplicate it | |
1215 | frag1 addr frag2 --- get second fragment | |
1216 | frag1 frag2 addr --- swap again | |
1217 | frag1 frag2 frag3 --- get third fragment | |
c906108c SS |
1218 | Notice that, since the third fragment is the last one, we don't |
1219 | bother duplicating the address this time. Now we have all the | |
1220 | fragments on the stack, and we can simply `or' them together, | |
1221 | yielding the final value of the bitfield. */ | |
1222 | ||
1223 | /* The first and one-after-last bits in the field, but rounded down | |
1224 | and up to byte boundaries. */ | |
1225 | int bound_start = (start / TARGET_CHAR_BIT) * TARGET_CHAR_BIT; | |
c5aa993b JM |
1226 | int bound_end = (((end + TARGET_CHAR_BIT - 1) |
1227 | / TARGET_CHAR_BIT) | |
1228 | * TARGET_CHAR_BIT); | |
c906108c SS |
1229 | |
1230 | /* current bit offset within the structure */ | |
1231 | int offset; | |
1232 | ||
1233 | /* The index in ops of the opcode we're considering. */ | |
1234 | int op; | |
1235 | ||
1236 | /* The number of fragments we generated in the process. Probably | |
1237 | equal to the number of `one' bits in bytesize, but who cares? */ | |
1238 | int fragment_count; | |
1239 | ||
1240 | /* Dereference any typedefs. */ | |
1241 | type = check_typedef (type); | |
1242 | ||
1243 | /* Can we fetch the number of bits requested at all? */ | |
1244 | if ((end - start) > ((1 << num_ops) * 8)) | |
8e65ff28 AC |
1245 | internal_error (__FILE__, __LINE__, |
1246 | "gen_bitfield_ref: bitfield too wide"); | |
c906108c SS |
1247 | |
1248 | /* Note that we know here that we only need to try each opcode once. | |
1249 | That may not be true on machines with weird byte sizes. */ | |
1250 | offset = bound_start; | |
1251 | fragment_count = 0; | |
1252 | for (op = num_ops - 1; op >= 0; op--) | |
1253 | { | |
1254 | /* number of bits that ops[op] would fetch */ | |
1255 | int op_size = 8 << op; | |
1256 | ||
1257 | /* The stack at this point, from bottom to top, contains zero or | |
c5aa993b JM |
1258 | more fragments, then the address. */ |
1259 | ||
c906108c SS |
1260 | /* Does this fetch fit within the bitfield? */ |
1261 | if (offset + op_size <= bound_end) | |
1262 | { | |
1263 | /* Is this the last fragment? */ | |
1264 | int last_frag = (offset + op_size == bound_end); | |
1265 | ||
c5aa993b JM |
1266 | if (!last_frag) |
1267 | ax_simple (ax, aop_dup); /* keep a copy of the address */ | |
1268 | ||
c906108c SS |
1269 | /* Add the offset. */ |
1270 | gen_offset (ax, offset / TARGET_CHAR_BIT); | |
1271 | ||
1272 | if (trace_kludge) | |
1273 | { | |
1274 | /* Record the area of memory we're about to fetch. */ | |
1275 | ax_trace_quick (ax, op_size / TARGET_CHAR_BIT); | |
1276 | } | |
1277 | ||
1278 | /* Perform the fetch. */ | |
1279 | ax_simple (ax, ops[op]); | |
c5aa993b JM |
1280 | |
1281 | /* Shift the bits we have to their proper position. | |
c906108c SS |
1282 | gen_left_shift will generate right shifts when the operand |
1283 | is negative. | |
1284 | ||
c5aa993b JM |
1285 | A big-endian field diagram to ponder: |
1286 | byte 0 byte 1 byte 2 byte 3 byte 4 byte 5 byte 6 byte 7 | |
1287 | +------++------++------++------++------++------++------++------+ | |
1288 | xxxxAAAAAAAAAAAAAAAAAAAAAAAAAAAABBBBBBBBBBBBBBBBCCCCCxxxxxxxxxxx | |
1289 | ^ ^ ^ ^ | |
1290 | bit number 16 32 48 53 | |
c906108c SS |
1291 | These are bit numbers as supplied by GDB. Note that the |
1292 | bit numbers run from right to left once you've fetched the | |
1293 | value! | |
1294 | ||
c5aa993b JM |
1295 | A little-endian field diagram to ponder: |
1296 | byte 7 byte 6 byte 5 byte 4 byte 3 byte 2 byte 1 byte 0 | |
1297 | +------++------++------++------++------++------++------++------+ | |
1298 | xxxxxxxxxxxAAAAABBBBBBBBBBBBBBBBCCCCCCCCCCCCCCCCCCCCCCCCCCCCxxxx | |
1299 | ^ ^ ^ ^ ^ | |
1300 | bit number 48 32 16 4 0 | |
1301 | ||
1302 | In both cases, the most significant end is on the left | |
1303 | (i.e. normal numeric writing order), which means that you | |
1304 | don't go crazy thinking about `left' and `right' shifts. | |
1305 | ||
1306 | We don't have to worry about masking yet: | |
1307 | - If they contain garbage off the least significant end, then we | |
1308 | must be looking at the low end of the field, and the right | |
1309 | shift will wipe them out. | |
1310 | - If they contain garbage off the most significant end, then we | |
1311 | must be looking at the most significant end of the word, and | |
1312 | the sign/zero extension will wipe them out. | |
1313 | - If we're in the interior of the word, then there is no garbage | |
1314 | on either end, because the ref operators zero-extend. */ | |
d7449b42 | 1315 | if (TARGET_BYTE_ORDER == BFD_ENDIAN_BIG) |
c906108c | 1316 | gen_left_shift (ax, end - (offset + op_size)); |
c5aa993b | 1317 | else |
c906108c SS |
1318 | gen_left_shift (ax, offset - start); |
1319 | ||
c5aa993b | 1320 | if (!last_frag) |
c906108c SS |
1321 | /* Bring the copy of the address up to the top. */ |
1322 | ax_simple (ax, aop_swap); | |
1323 | ||
1324 | offset += op_size; | |
1325 | fragment_count++; | |
1326 | } | |
1327 | } | |
1328 | ||
1329 | /* Generate enough bitwise `or' operations to combine all the | |
1330 | fragments we left on the stack. */ | |
1331 | while (fragment_count-- > 1) | |
1332 | ax_simple (ax, aop_bit_or); | |
1333 | ||
1334 | /* Sign- or zero-extend the value as appropriate. */ | |
1335 | ((TYPE_UNSIGNED (type) ? ax_zero_ext : ax_ext) (ax, end - start)); | |
1336 | ||
1337 | /* This is *not* an lvalue. Ugh. */ | |
1338 | value->kind = axs_rvalue; | |
1339 | value->type = type; | |
1340 | } | |
1341 | ||
1342 | ||
1343 | /* Generate code to reference the member named FIELD of a structure or | |
1344 | union. The top of the stack, as described by VALUE, should have | |
1345 | type (pointer to a)* struct/union. OPERATOR_NAME is the name of | |
1346 | the operator being compiled, and OPERAND_NAME is the kind of thing | |
1347 | it operates on; we use them in error messages. */ | |
1348 | static void | |
fba45db2 KB |
1349 | gen_struct_ref (struct agent_expr *ax, struct axs_value *value, char *field, |
1350 | char *operator_name, char *operand_name) | |
c906108c SS |
1351 | { |
1352 | struct type *type; | |
1353 | int i; | |
1354 | ||
1355 | /* Follow pointers until we reach a non-pointer. These aren't the C | |
1356 | semantics, but they're what the normal GDB evaluator does, so we | |
1357 | should at least be consistent. */ | |
0004e5a2 | 1358 | while (TYPE_CODE (value->type) == TYPE_CODE_PTR) |
c906108c SS |
1359 | { |
1360 | gen_usual_unary (ax, value); | |
1361 | gen_deref (ax, value); | |
1362 | } | |
e8860ec2 | 1363 | type = check_typedef (value->type); |
c906108c SS |
1364 | |
1365 | /* This must yield a structure or a union. */ | |
1366 | if (TYPE_CODE (type) != TYPE_CODE_STRUCT | |
1367 | && TYPE_CODE (type) != TYPE_CODE_UNION) | |
1368 | error ("The left operand of `%s' is not a %s.", | |
1369 | operator_name, operand_name); | |
1370 | ||
1371 | /* And it must be in memory; we don't deal with structure rvalues, | |
1372 | or structures living in registers. */ | |
1373 | if (value->kind != axs_lvalue_memory) | |
1374 | error ("Structure does not live in memory."); | |
1375 | ||
1376 | i = find_field (type, field); | |
c5aa993b | 1377 | |
c906108c SS |
1378 | /* Is this a bitfield? */ |
1379 | if (TYPE_FIELD_PACKED (type, i)) | |
1380 | gen_bitfield_ref (ax, value, TYPE_FIELD_TYPE (type, i), | |
1381 | TYPE_FIELD_BITPOS (type, i), | |
1382 | (TYPE_FIELD_BITPOS (type, i) | |
1383 | + TYPE_FIELD_BITSIZE (type, i))); | |
1384 | else | |
1385 | { | |
1386 | gen_offset (ax, TYPE_FIELD_BITPOS (type, i) / TARGET_CHAR_BIT); | |
1387 | value->kind = axs_lvalue_memory; | |
1388 | value->type = TYPE_FIELD_TYPE (type, i); | |
1389 | } | |
1390 | } | |
1391 | ||
1392 | ||
1393 | /* Generate code for GDB's magical `repeat' operator. | |
1394 | LVALUE @ INT creates an array INT elements long, and whose elements | |
1395 | have the same type as LVALUE, located in memory so that LVALUE is | |
1396 | its first element. For example, argv[0]@argc gives you the array | |
1397 | of command-line arguments. | |
1398 | ||
1399 | Unfortunately, because we have to know the types before we actually | |
1400 | have a value for the expression, we can't implement this perfectly | |
1401 | without changing the type system, having values that occupy two | |
1402 | stack slots, doing weird things with sizeof, etc. So we require | |
1403 | the right operand to be a constant expression. */ | |
1404 | static void | |
fba45db2 KB |
1405 | gen_repeat (union exp_element **pc, struct agent_expr *ax, |
1406 | struct axs_value *value) | |
c906108c SS |
1407 | { |
1408 | struct axs_value value1; | |
1409 | /* We don't want to turn this into an rvalue, so no conversions | |
1410 | here. */ | |
1411 | gen_expr (pc, ax, &value1); | |
1412 | if (value1.kind != axs_lvalue_memory) | |
1413 | error ("Left operand of `@' must be an object in memory."); | |
1414 | ||
1415 | /* Evaluate the length; it had better be a constant. */ | |
1416 | { | |
1417 | struct value *v = const_expr (pc); | |
1418 | int length; | |
1419 | ||
c5aa993b | 1420 | if (!v) |
c906108c | 1421 | error ("Right operand of `@' must be a constant, in agent expressions."); |
0004e5a2 | 1422 | if (TYPE_CODE (v->type) != TYPE_CODE_INT) |
c906108c SS |
1423 | error ("Right operand of `@' must be an integer."); |
1424 | length = value_as_long (v); | |
1425 | if (length <= 0) | |
1426 | error ("Right operand of `@' must be positive."); | |
1427 | ||
1428 | /* The top of the stack is already the address of the object, so | |
1429 | all we need to do is frob the type of the lvalue. */ | |
1430 | { | |
1431 | /* FIXME-type-allocation: need a way to free this type when we are | |
c5aa993b | 1432 | done with it. */ |
c906108c | 1433 | struct type *range |
c5aa993b | 1434 | = create_range_type (0, builtin_type_int, 0, length - 1); |
c906108c SS |
1435 | struct type *array = create_array_type (0, value1.type, range); |
1436 | ||
1437 | value->kind = axs_lvalue_memory; | |
1438 | value->type = array; | |
1439 | } | |
1440 | } | |
1441 | } | |
1442 | ||
1443 | ||
1444 | /* Emit code for the `sizeof' operator. | |
1445 | *PC should point at the start of the operand expression; we advance it | |
1446 | to the first instruction after the operand. */ | |
1447 | static void | |
fba45db2 KB |
1448 | gen_sizeof (union exp_element **pc, struct agent_expr *ax, |
1449 | struct axs_value *value) | |
c906108c SS |
1450 | { |
1451 | /* We don't care about the value of the operand expression; we only | |
1452 | care about its type. However, in the current arrangement, the | |
1453 | only way to find an expression's type is to generate code for it. | |
1454 | So we generate code for the operand, and then throw it away, | |
1455 | replacing it with code that simply pushes its size. */ | |
1456 | int start = ax->len; | |
1457 | gen_expr (pc, ax, value); | |
1458 | ||
1459 | /* Throw away the code we just generated. */ | |
1460 | ax->len = start; | |
c5aa993b | 1461 | |
c906108c SS |
1462 | ax_const_l (ax, TYPE_LENGTH (value->type)); |
1463 | value->kind = axs_rvalue; | |
1464 | value->type = builtin_type_int; | |
1465 | } | |
c906108c | 1466 | \f |
c5aa993b | 1467 | |
c906108c SS |
1468 | /* Generating bytecode from GDB expressions: general recursive thingy */ |
1469 | ||
1470 | /* A gen_expr function written by a Gen-X'er guy. | |
1471 | Append code for the subexpression of EXPR starting at *POS_P to AX. */ | |
1472 | static void | |
fba45db2 KB |
1473 | gen_expr (union exp_element **pc, struct agent_expr *ax, |
1474 | struct axs_value *value) | |
c906108c SS |
1475 | { |
1476 | /* Used to hold the descriptions of operand expressions. */ | |
1477 | struct axs_value value1, value2; | |
1478 | enum exp_opcode op = (*pc)[0].opcode; | |
1479 | ||
1480 | /* If we're looking at a constant expression, just push its value. */ | |
1481 | { | |
1482 | struct value *v = maybe_const_expr (pc); | |
c5aa993b | 1483 | |
c906108c SS |
1484 | if (v) |
1485 | { | |
1486 | ax_const_l (ax, value_as_long (v)); | |
1487 | value->kind = axs_rvalue; | |
1488 | value->type = check_typedef (VALUE_TYPE (v)); | |
1489 | return; | |
1490 | } | |
1491 | } | |
1492 | ||
1493 | /* Otherwise, go ahead and generate code for it. */ | |
1494 | switch (op) | |
1495 | { | |
1496 | /* Binary arithmetic operators. */ | |
1497 | case BINOP_ADD: | |
1498 | case BINOP_SUB: | |
1499 | case BINOP_MUL: | |
1500 | case BINOP_DIV: | |
1501 | case BINOP_REM: | |
1502 | case BINOP_SUBSCRIPT: | |
1503 | case BINOP_BITWISE_AND: | |
1504 | case BINOP_BITWISE_IOR: | |
1505 | case BINOP_BITWISE_XOR: | |
1506 | (*pc)++; | |
1507 | gen_expr (pc, ax, &value1); | |
1508 | gen_usual_unary (ax, &value1); | |
1509 | gen_expr (pc, ax, &value2); | |
1510 | gen_usual_unary (ax, &value2); | |
1511 | gen_usual_arithmetic (ax, &value1, &value2); | |
1512 | switch (op) | |
1513 | { | |
1514 | case BINOP_ADD: | |
1515 | gen_add (ax, value, &value1, &value2, "addition"); | |
1516 | break; | |
1517 | case BINOP_SUB: | |
1518 | gen_sub (ax, value, &value1, &value2); | |
1519 | break; | |
1520 | case BINOP_MUL: | |
1521 | gen_binop (ax, value, &value1, &value2, | |
1522 | aop_mul, aop_mul, 1, "multiplication"); | |
1523 | break; | |
1524 | case BINOP_DIV: | |
1525 | gen_binop (ax, value, &value1, &value2, | |
1526 | aop_div_signed, aop_div_unsigned, 1, "division"); | |
1527 | break; | |
1528 | case BINOP_REM: | |
1529 | gen_binop (ax, value, &value1, &value2, | |
1530 | aop_rem_signed, aop_rem_unsigned, 1, "remainder"); | |
1531 | break; | |
1532 | case BINOP_SUBSCRIPT: | |
1533 | gen_add (ax, value, &value1, &value2, "array subscripting"); | |
1534 | if (TYPE_CODE (value->type) != TYPE_CODE_PTR) | |
1535 | error ("Illegal combination of types in array subscripting."); | |
1536 | gen_deref (ax, value); | |
1537 | break; | |
1538 | case BINOP_BITWISE_AND: | |
1539 | gen_binop (ax, value, &value1, &value2, | |
1540 | aop_bit_and, aop_bit_and, 0, "bitwise and"); | |
1541 | break; | |
1542 | ||
1543 | case BINOP_BITWISE_IOR: | |
1544 | gen_binop (ax, value, &value1, &value2, | |
1545 | aop_bit_or, aop_bit_or, 0, "bitwise or"); | |
1546 | break; | |
1547 | ||
1548 | case BINOP_BITWISE_XOR: | |
1549 | gen_binop (ax, value, &value1, &value2, | |
1550 | aop_bit_xor, aop_bit_xor, 0, "bitwise exclusive-or"); | |
1551 | break; | |
1552 | ||
1553 | default: | |
1554 | /* We should only list operators in the outer case statement | |
c5aa993b | 1555 | that we actually handle in the inner case statement. */ |
8e65ff28 AC |
1556 | internal_error (__FILE__, __LINE__, |
1557 | "gen_expr: op case sets don't match"); | |
c906108c SS |
1558 | } |
1559 | break; | |
1560 | ||
1561 | /* Note that we need to be a little subtle about generating code | |
c5aa993b JM |
1562 | for comma. In C, we can do some optimizations here because |
1563 | we know the left operand is only being evaluated for effect. | |
1564 | However, if the tracing kludge is in effect, then we always | |
1565 | need to evaluate the left hand side fully, so that all the | |
1566 | variables it mentions get traced. */ | |
c906108c SS |
1567 | case BINOP_COMMA: |
1568 | (*pc)++; | |
1569 | gen_expr (pc, ax, &value1); | |
1570 | /* Don't just dispose of the left operand. We might be tracing, | |
c5aa993b JM |
1571 | in which case we want to emit code to trace it if it's an |
1572 | lvalue. */ | |
c906108c SS |
1573 | gen_traced_pop (ax, &value1); |
1574 | gen_expr (pc, ax, value); | |
1575 | /* It's the consumer's responsibility to trace the right operand. */ | |
1576 | break; | |
c5aa993b | 1577 | |
c906108c SS |
1578 | case OP_LONG: /* some integer constant */ |
1579 | { | |
1580 | struct type *type = (*pc)[1].type; | |
1581 | LONGEST k = (*pc)[2].longconst; | |
1582 | (*pc) += 4; | |
1583 | gen_int_literal (ax, value, k, type); | |
1584 | } | |
c5aa993b | 1585 | break; |
c906108c SS |
1586 | |
1587 | case OP_VAR_VALUE: | |
1588 | gen_var_ref (ax, value, (*pc)[2].symbol); | |
1589 | (*pc) += 4; | |
1590 | break; | |
1591 | ||
1592 | case OP_REGISTER: | |
1593 | { | |
1594 | int reg = (int) (*pc)[1].longconst; | |
1595 | (*pc) += 3; | |
1596 | value->kind = axs_lvalue_register; | |
1597 | value->u.reg = reg; | |
1598 | value->type = REGISTER_VIRTUAL_TYPE (reg); | |
1599 | } | |
c5aa993b | 1600 | break; |
c906108c SS |
1601 | |
1602 | case OP_INTERNALVAR: | |
1603 | error ("GDB agent expressions cannot use convenience variables."); | |
1604 | ||
c5aa993b | 1605 | /* Weirdo operator: see comments for gen_repeat for details. */ |
c906108c SS |
1606 | case BINOP_REPEAT: |
1607 | /* Note that gen_repeat handles its own argument evaluation. */ | |
1608 | (*pc)++; | |
1609 | gen_repeat (pc, ax, value); | |
1610 | break; | |
1611 | ||
1612 | case UNOP_CAST: | |
1613 | { | |
1614 | struct type *type = (*pc)[1].type; | |
1615 | (*pc) += 3; | |
1616 | gen_expr (pc, ax, value); | |
1617 | gen_cast (ax, value, type); | |
1618 | } | |
c5aa993b | 1619 | break; |
c906108c SS |
1620 | |
1621 | case UNOP_MEMVAL: | |
1622 | { | |
1623 | struct type *type = check_typedef ((*pc)[1].type); | |
1624 | (*pc) += 3; | |
1625 | gen_expr (pc, ax, value); | |
1626 | /* I'm not sure I understand UNOP_MEMVAL entirely. I think | |
1627 | it's just a hack for dealing with minsyms; you take some | |
1628 | integer constant, pretend it's the address of an lvalue of | |
1629 | the given type, and dereference it. */ | |
1630 | if (value->kind != axs_rvalue) | |
1631 | /* This would be weird. */ | |
8e65ff28 AC |
1632 | internal_error (__FILE__, __LINE__, |
1633 | "gen_expr: OP_MEMVAL operand isn't an rvalue???"); | |
c906108c SS |
1634 | value->type = type; |
1635 | value->kind = axs_lvalue_memory; | |
1636 | } | |
c5aa993b | 1637 | break; |
c906108c SS |
1638 | |
1639 | case UNOP_NEG: | |
1640 | (*pc)++; | |
1641 | /* -FOO is equivalent to 0 - FOO. */ | |
1642 | gen_int_literal (ax, &value1, (LONGEST) 0, builtin_type_int); | |
c5aa993b | 1643 | gen_usual_unary (ax, &value1); /* shouldn't do much */ |
c906108c SS |
1644 | gen_expr (pc, ax, &value2); |
1645 | gen_usual_unary (ax, &value2); | |
1646 | gen_usual_arithmetic (ax, &value1, &value2); | |
1647 | gen_sub (ax, value, &value1, &value2); | |
1648 | break; | |
1649 | ||
1650 | case UNOP_LOGICAL_NOT: | |
1651 | (*pc)++; | |
1652 | gen_expr (pc, ax, value); | |
1653 | gen_logical_not (ax, value); | |
1654 | break; | |
1655 | ||
1656 | case UNOP_COMPLEMENT: | |
1657 | (*pc)++; | |
1658 | gen_expr (pc, ax, value); | |
1659 | gen_complement (ax, value); | |
1660 | break; | |
1661 | ||
1662 | case UNOP_IND: | |
1663 | (*pc)++; | |
1664 | gen_expr (pc, ax, value); | |
1665 | gen_usual_unary (ax, value); | |
1666 | if (TYPE_CODE (value->type) != TYPE_CODE_PTR) | |
1667 | error ("Argument of unary `*' is not a pointer."); | |
1668 | gen_deref (ax, value); | |
1669 | break; | |
1670 | ||
1671 | case UNOP_ADDR: | |
1672 | (*pc)++; | |
1673 | gen_expr (pc, ax, value); | |
1674 | gen_address_of (ax, value); | |
1675 | break; | |
1676 | ||
1677 | case UNOP_SIZEOF: | |
1678 | (*pc)++; | |
1679 | /* Notice that gen_sizeof handles its own operand, unlike most | |
c5aa993b JM |
1680 | of the other unary operator functions. This is because we |
1681 | have to throw away the code we generate. */ | |
c906108c SS |
1682 | gen_sizeof (pc, ax, value); |
1683 | break; | |
1684 | ||
1685 | case STRUCTOP_STRUCT: | |
1686 | case STRUCTOP_PTR: | |
1687 | { | |
1688 | int length = (*pc)[1].longconst; | |
1689 | char *name = &(*pc)[2].string; | |
1690 | ||
1691 | (*pc) += 4 + BYTES_TO_EXP_ELEM (length + 1); | |
1692 | gen_expr (pc, ax, value); | |
1693 | if (op == STRUCTOP_STRUCT) | |
1694 | gen_struct_ref (ax, value, name, ".", "structure or union"); | |
1695 | else if (op == STRUCTOP_PTR) | |
1696 | gen_struct_ref (ax, value, name, "->", | |
1697 | "pointer to a structure or union"); | |
1698 | else | |
1699 | /* If this `if' chain doesn't handle it, then the case list | |
c5aa993b | 1700 | shouldn't mention it, and we shouldn't be here. */ |
8e65ff28 AC |
1701 | internal_error (__FILE__, __LINE__, |
1702 | "gen_expr: unhandled struct case"); | |
c906108c | 1703 | } |
c5aa993b | 1704 | break; |
c906108c SS |
1705 | |
1706 | case OP_TYPE: | |
1707 | error ("Attempt to use a type name as an expression."); | |
1708 | ||
1709 | default: | |
1710 | error ("Unsupported operator in expression."); | |
1711 | } | |
1712 | } | |
c906108c | 1713 | \f |
c5aa993b JM |
1714 | |
1715 | ||
c906108c SS |
1716 | /* Generating bytecode from GDB expressions: driver */ |
1717 | ||
1718 | /* Given a GDB expression EXPR, produce a string of agent bytecode | |
1719 | which computes its value. Return the agent expression, and set | |
1720 | *VALUE to describe its type, and whether it's an lvalue or rvalue. */ | |
1721 | struct agent_expr * | |
fba45db2 | 1722 | expr_to_agent (struct expression *expr, struct axs_value *value) |
c906108c SS |
1723 | { |
1724 | struct cleanup *old_chain = 0; | |
6426a772 | 1725 | struct agent_expr *ax = new_agent_expr (0); |
c906108c SS |
1726 | union exp_element *pc; |
1727 | ||
f23d52e0 | 1728 | old_chain = make_cleanup_free_agent_expr (ax); |
c906108c SS |
1729 | |
1730 | pc = expr->elts; | |
1731 | trace_kludge = 0; | |
1732 | gen_expr (&pc, ax, value); | |
1733 | ||
1734 | /* We have successfully built the agent expr, so cancel the cleanup | |
1735 | request. If we add more cleanups that we always want done, this | |
1736 | will have to get more complicated. */ | |
1737 | discard_cleanups (old_chain); | |
1738 | return ax; | |
1739 | } | |
1740 | ||
1741 | ||
6426a772 | 1742 | #if 0 /* not used */ |
c906108c SS |
1743 | /* Given a GDB expression EXPR denoting an lvalue in memory, produce a |
1744 | string of agent bytecode which will leave its address and size on | |
1745 | the top of stack. Return the agent expression. | |
1746 | ||
1747 | Not sure this function is useful at all. */ | |
1748 | struct agent_expr * | |
fba45db2 | 1749 | expr_to_address_and_size (struct expression *expr) |
c906108c SS |
1750 | { |
1751 | struct axs_value value; | |
1752 | struct agent_expr *ax = expr_to_agent (expr, &value); | |
1753 | ||
1754 | /* Complain if the result is not a memory lvalue. */ | |
1755 | if (value.kind != axs_lvalue_memory) | |
1756 | { | |
1757 | free_agent_expr (ax); | |
1758 | error ("Expression does not denote an object in memory."); | |
1759 | } | |
1760 | ||
1761 | /* Push the object's size on the stack. */ | |
1762 | ax_const_l (ax, TYPE_LENGTH (value.type)); | |
1763 | ||
1764 | return ax; | |
1765 | } | |
6426a772 | 1766 | #endif |
c906108c SS |
1767 | |
1768 | /* Given a GDB expression EXPR, return bytecode to trace its value. | |
1769 | The result will use the `trace' and `trace_quick' bytecodes to | |
1770 | record the value of all memory touched by the expression. The | |
1771 | caller can then use the ax_reqs function to discover which | |
1772 | registers it relies upon. */ | |
1773 | struct agent_expr * | |
fba45db2 | 1774 | gen_trace_for_expr (CORE_ADDR scope, struct expression *expr) |
c906108c SS |
1775 | { |
1776 | struct cleanup *old_chain = 0; | |
1777 | struct agent_expr *ax = new_agent_expr (scope); | |
1778 | union exp_element *pc; | |
1779 | struct axs_value value; | |
1780 | ||
f23d52e0 | 1781 | old_chain = make_cleanup_free_agent_expr (ax); |
c906108c SS |
1782 | |
1783 | pc = expr->elts; | |
1784 | trace_kludge = 1; | |
1785 | gen_expr (&pc, ax, &value); | |
1786 | ||
1787 | /* Make sure we record the final object, and get rid of it. */ | |
1788 | gen_traced_pop (ax, &value); | |
1789 | ||
1790 | /* Oh, and terminate. */ | |
1791 | ax_simple (ax, aop_end); | |
1792 | ||
1793 | /* We have successfully built the agent expr, so cancel the cleanup | |
1794 | request. If we add more cleanups that we always want done, this | |
1795 | will have to get more complicated. */ | |
1796 | discard_cleanups (old_chain); | |
1797 | return ax; | |
1798 | } | |
c5aa993b | 1799 | \f |
c906108c SS |
1800 | |
1801 | ||
c906108c SS |
1802 | /* The "agent" command, for testing: compile and disassemble an expression. */ |
1803 | ||
1804 | static void | |
fba45db2 | 1805 | print_axs_value (struct ui_file *f, struct axs_value *value) |
c906108c SS |
1806 | { |
1807 | switch (value->kind) | |
1808 | { | |
1809 | case axs_rvalue: | |
1810 | fputs_filtered ("rvalue", f); | |
1811 | break; | |
1812 | ||
1813 | case axs_lvalue_memory: | |
1814 | fputs_filtered ("memory lvalue", f); | |
1815 | break; | |
1816 | ||
1817 | case axs_lvalue_register: | |
1818 | fprintf_filtered (f, "register %d lvalue", value->u.reg); | |
1819 | break; | |
1820 | } | |
1821 | ||
1822 | fputs_filtered (" : ", f); | |
1823 | type_print (value->type, "", f, -1); | |
1824 | } | |
1825 | ||
1826 | ||
1827 | static void | |
fba45db2 | 1828 | agent_command (char *exp, int from_tty) |
c906108c SS |
1829 | { |
1830 | struct cleanup *old_chain = 0; | |
1831 | struct expression *expr; | |
1832 | struct agent_expr *agent; | |
6426a772 | 1833 | struct frame_info *fi = get_current_frame (); /* need current scope */ |
c906108c SS |
1834 | |
1835 | /* We don't deal with overlay debugging at the moment. We need to | |
1836 | think more carefully about this. If you copy this code into | |
1837 | another command, change the error message; the user shouldn't | |
1838 | have to know anything about agent expressions. */ | |
1839 | if (overlay_debugging) | |
1840 | error ("GDB can't do agent expression translation with overlays."); | |
1841 | ||
1842 | if (exp == 0) | |
1843 | error_no_arg ("expression to translate"); | |
c5aa993b | 1844 | |
c906108c | 1845 | expr = parse_expression (exp); |
c13c43fd | 1846 | old_chain = make_cleanup (free_current_contents, &expr); |
bdd78e62 | 1847 | agent = gen_trace_for_expr (get_frame_pc (fi), expr); |
f23d52e0 | 1848 | make_cleanup_free_agent_expr (agent); |
c906108c | 1849 | ax_print (gdb_stdout, agent); |
085dd6e6 JM |
1850 | |
1851 | /* It would be nice to call ax_reqs here to gather some general info | |
1852 | about the expression, and then print out the result. */ | |
c906108c SS |
1853 | |
1854 | do_cleanups (old_chain); | |
1855 | dont_repeat (); | |
1856 | } | |
c906108c | 1857 | \f |
c5aa993b | 1858 | |
c906108c SS |
1859 | /* Initialization code. */ |
1860 | ||
a14ed312 | 1861 | void _initialize_ax_gdb (void); |
c906108c | 1862 | void |
fba45db2 | 1863 | _initialize_ax_gdb (void) |
c906108c | 1864 | { |
c906108c SS |
1865 | add_cmd ("agent", class_maintenance, agent_command, |
1866 | "Translate an expression into remote agent bytecode.", | |
1867 | &maintenancelist); | |
1868 | } |